## What is the Ajax crawling scheme specification?

### What is the "_escaped_fragment_=" query parameter?

The `_escaped_fragment_=` parameter is a particular URL query parameter defined in the old
Ajax crawling scheme specification. It allows HTTP servers to detect when a bot supporting the Ajax
crawling scheme is requesting an HTML snapshot.

With the new [Dynamic Rendering recommendation](/content/faq/what-is-dynamic-rendering/index.html), this parameter is obsolete and not needed anymore.

If you have questions or comments about this FAQ, please contact us by [email](mailto:contact@seo4ajax.com).